It wouldn’t. At least not from a pistol. Handguns usually lack the ability to completely shatter the skull, they’ll still pierce the skull, but it will be a (figuratively) clean entry wound.
Gunshot wounds vary based on how far away the gun is from the victim. Bullet velocity, and caliber also affect the wound, but it’s not a huge consideration most of the time. Now, keep in mind, this is all from modern forensics. But, the basic idea of how a gun works hasn’t really changed in the last 800 years. That is to say: boom = splat.
Gunshots over two feet from the firearm will result in a small circular wound in the victim. This will usually be slightly smaller than the bullet. This is because the skin stretches to accommodate the bullet before it penetrates. It also bunches, creating something called an abrasion collar, which is an inflamed ring around the entry wound. The collar is usually black or blue as it picks up grime and oil from the bullet as it passes into the deeper tissue.
Between two inches and two feet (roughly) there will be a pattern of burning and unburned powder that gets forced into the skin. This is called stippling. It creates tiny pinpoint hemorrhages under the skin. The closer to the victim, the smaller the ring.
It’s worth pointing out, this will occur if you shoot someone with a blank at very close range, and you can kill someone with blanks because of stippling.
Shooting someone with the gun pressed against them will result in a contact wound. In these cases the expanding gasses from the gunshot will vent into the victim, resulting in a star shaped eruption under the skin. These are big messy wounds… but they still won’t cause someone’s skull to cave in, or even for their face to be completely unrecognizable.
As an aside: These are the same gasses you’re trying to reduce when suppressing a firearm. I’m not sure what kind of a contact wound you’d get off a suppressed firearm.
Now, a shotgun loaded with buckshot, at medium range, can turn someone’s face into hamburger. The 18th century equivalent would be a blunderbuss. These were loaded with whatever shrapnel came to hand, and were really nasty weapons. So, if you haven’t looked into them, that’s probably what you want, even if they weren’t one handed.
If your character hot loaded their pistol and forgot (or chose not) to load a ball, the resulting spray at close range might be enough to sear their opponent’s face. This should kill them, but it is theoretically possible for a character could survive that. Though, getting shot in the head is surprisingly survivable, in general.
Now, that’s if we’re talking about the entry wound. Exit wounds are usually larger and ragged, particularly if we’re talking about 18th century firearms (there’s some modern exceptions). If your character was executed by a gunshot to the back of the head, it’s possible, if the angle was right, for the bullet to take most of their face off on the way out. Obviously, this isn’t a survivable wound, but it is possible.
In a modern context, jacketed and high velocity rounds tend to produce exit wounds that are very similar to entry wounds. When the shooter was more than a couple feet from the victim, and using one of these rounds, it can sometimes be difficult for an ME to differentiate between a victim’s entrance and exit wound.
Incidentally, Teflon coated rounds would actually fall into the high velocity group there. These gained a reputation for armor penetration, but the actual cause is the Teflon reduces drag on the bullet, improving its flatness. Either way, if these miss bone on the way through, they’re going to leave a similar entrance and exit wound.
Soft rounds can leave really messy exit wounds. If they impact a bone straight on, they can shear apart, it can even leave multiple wounds, or they can flatten out and wedge against the bone, leaving no exit wound whatsoever. If they flatten out, continue moving and start to tumble they can leave tiny exit wounds that look like minor lacerations.
As I’ve said before: bullets are kinda random.
Oh, and a reminder, when it comes to gunshot wounds, Google Image Search hates you, but it is useful if you really, really, want to see what this stuff looks like. Just remember to bring a strong stomach.
archieandkobi said: Apparently, the pistols back then were really weak. I’ve heard of cases where people tried to shoot themselves and failed because the balls didn’t even get through their skulls. Most seemed to suffer concussion.
That would actually depend on how much powder the loaded. One of the quirks with pre-19th century firearms was, you were responsible for the amount of powder you loaded into the weapon for each round. This was partially dealt with by using premeasured paper cartridges that you would tear open and dump down the barrel. But, those weren’t universal, much like modern speedloaders aren’t something everyone uses. If you don’t put enough powder down the barrel, it’s not going to clear it with enough force.
I’m guessing the cases you’re looking at were the result of under loading a pistol, but, I am guessing there.